SAN DIEGO – Gilbert Melendez is becoming an increasingly bigger fish in an increasingly smaller pond.

The Strikeforce lightweight champion and top-10 pound-for-pound fighter earned a shutout unanimous-decision victory over noted striker Jorge Masvidal in his latest title defense.

The bout headlined the Showtime-televised main card of “Strikeforce: Melendez vs. Masvidal,” which took place at Valley View Casino Center in San Diego.

For every strike Masvidal threw, he ate two or three. It both slowed Masvidal’s attacks and allowed Melendez to gain confidence throughout the fight.

After an initial feeling-out process, Melendez took the lead with effective two-punch combinations and some lunging punches. Masvidal kept him honest with low kicks and leaping knees, but Melendez closed out the round with a guillotine-choke attempt, knees to the head and continued two-punch combos.

The second round initially started slow, but Melendez returned to combos and straight rights to score points. Masvidal returned fire with body shots and some effective jabs, but Melendez was the clear aggressor in the round and dictated the pace.

Melendez clearly had built some confidence by the third round, and he simply swung through his opponent’s offense to dish out his own punches. Pesky jabs, body shots and straight rights to the chin all landed flush. Masvidal mixed in some solid counter-shots and a pair of vicious body punches, but he simply couldn’t slow Melendez’s advances.

The fourth and fifth rounds provided much of the same. Although Masvidal did damage to the champ’s face and caused some heavy swelling around the right eye, Melendez landed the cleaner shots, initiated more of the action, and left his opponent confused and frustrated during the exchanges. Masvidal often waved him in only to be tagged with more punches from the light-footed Melendez.

In the end, Melendez defended his belt and earned the unanimous-decision win via 50-45, 50-45 and 49-46 scores.

“I had to do what I had to do,” Melendez said. “Jorge isn’t the easiest matchup, especially stylistically for me. … But I beat him at his own game. I think I’m better than a decent striker.

“I wanted to get the takedown, but he’s just not an easy guy to take down. He has really good movement, really good distance, and really good length. And he doesn’t really walk forward, so it’s not really there.”

Melendez (20-2 MMA, 10-1 SF) now has won six straight fights and makes his third straight defense of the title (and fourth overall). With Strikeforce’s recent new deal with Showtime, officials said Melendez will stay in the organization rather than make a long-expected move to the UFC. Sadly, though, Melendez again proved that he needs a step up in competition that he’s unlikely to get in Strikeforce.

“I’m proud to be a part of Strikeforce,” Melendez said. “Showtime is amazing. But you know what? They need to bring some guys over here to challenge me. I’d like to challenge the champ, whoever it is in the UFC. Come to my hexagon, and let’s fight.”

Masvidal (22-7 MMA, 2-1 SF), who has defeated notables K.J. Noons and Billy Evangelista in previous bouts to earn the title shot, suffers his first Strikeforce loss.